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  • Silverlight Cream for June 06, 2010 -- #876

    - by Dave Campbell
    In this Issue: Brian Genisio, Michael Washington, Fons Sonnemans , Don Burnett, Xianzhong Zhu, Mike Snow, Jesse Liberty, Victor Gaudioso, David Kelley(-2-), and Matias Bonaventura . Shoutout: Anoop has a good post up: MEF or Managed Extensibility Framework and Lazy – Being Lazy with MEF, Custom Export Attributes etc Jesse Liberty's got a good post up if you are just Getting Started With Silverlight: A Path Through The Learning Material John Papa reports Updates and New Home for Sticky Plugin Tim Heuer announced Silverlight 4 Theme refresh including RIA Services templates From SilverlightCream.com: Adventures in MVVM – ViewModel Location and Creation Brian Genisio has a post up about ViewModels and how he attaches them to his views. Some discssion of MVVMLight, and other external links plus the code for the project. Simplified MEF: Dynamically Loading a Silverlight .xap Michael Washington has a good tutorial up on MEF, Silverlight, and ViewModel. In Michael's words: The goal here is to give you a quick easy win. You will be able to understand this one. You will come away with something you can use, and you will be able to tell your fellow colleagues, "MEF? yeah I'm using that, good stuff Touch Gesture Triggers for Windows Phone 7 projects in Blend 4.0 Fons Sonnemans has a post up about touch gestures for WP7 -- he's got 3 of them implemented using triggers, plus an external link to another, and the source. What the Heck is “MEF” for, and what Silverlight designers need to know about it? Don Burnett is also talking MEF... he does a good job of introducing MEF if you're not acquainted yet, plus some external information. Write Your Custom Effect Components in Silverlight 3 Xianzhong Zhu has a post up walking you through creating your own Custom Effect for Blend and Silverlight 3 ... lots of external links and the source project. Silverlight Tip of the Day #28 – Text Trimming Mike Snow's Tip #28 is about Text Trimming... what it does, and how it differs from WPF Windows Phone 7: Lists, Page Animation and oData Jesse Liberty called this a mini-tutorial, but it's not so mini... great tutorial on WP7, data, lists, and page transitions... oh, and the data is OData too... New Silveright Video Tutorial: How to Do Hit Detection Victor Gaudioso's latest video tutorial is up and he's demonstrating how to do Silverlight HitTesting via code from Andy Beaulieu Dependency Properties Made Easy Need a quick pick-up on Dependency Properties? David Kelley has a short post about them on his blog. Isolated Storage Made Easy David Kelley also has a quick post up about Isolated Storage ... going to keep an eye out for more of these quick "Made Easy" posts from David. Prism 4.0 First Drop – MVVM Matias Bonaventura has a post up about the recent Prism 4.0 drop and highlights a bunch of the features/enhancements in this... some code snippets and a linnk out to the CodePlex drop. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Silverlight Cream for April 11, 2010 -- #836

    - by Dave Campbell
    In this Issue: Rénald Nollet, Roboblob, Laurent Bugnion, Timmy Kokke, Michael Sync(-2-), Victor Gaudioso, and Bill Reiss. Brought to you from a tiny table in my no-tell-motelTM in 'Vegas AKA "cheaper than anywhere else" and the WiFi is free and smokin'... From SilverlightCream.com: Sync your Silverlight out-of-browser application data without service but with Dropbox Rénald Nollet is in good company (Walt Ritscher) because he's demo'ing synching OOB apps with dropbox. Unit Testable WCF Web Services in MVVM and Silverlight 4 Roboblob is discussing calling WCF Web Services from a Silverlight MVVM app... something he's been avoiding up to now. Good long code and text-filled article, with the project to download. Using commands with ApplicationBarMenuItem and ApplicationBarButton in Windows Phone 7 I almost missed this post by Laurent Bugnion, on how to get around the problem of not being able to attach commands to the ApplicationBarMenuItem and ApplicationBarButton in WP7. He gets around it with (gasp) code behind :) Introducing jLight – Talking to the DOM using Silverlight and jQuery. Oh boy... if you haven't been using jQuery yet, this should get it going for you... Timmy Kokke has produced jLight which brings jQuery into Silverlight for ease of DOM interaction... and it's on CodePlex! Test-Driven Development in Windows Phone7 – Part 1: Unit Testing with Silverlight for Phone7 Michael Sync's starting a series on TDD with Silverlight on WP7. Great tutorial and all the code is available. Tip: “Object reference not set to an instance of an object” Error in Silverlight for Windows Phone 7 Michael Sync also has a tip up for the resolution of an error we've all seen in all sorts of development, but now in WP7, and the workaround is deceptively simple. New Silverlight Video Tutorial: How to Create Gradients Victor Gaudioso has a new video tutorial up for creating gradients in Expression Blend... don't fumble around in Blend... learn from the master! Space Rocks game step 8: Hyperspace Bill Reiss is up to episode 8 in his Silverlight game series now... this latest is on Hyperspace ... don'cha wish you could just do that? My trip to 'Vegas would have been a lot faster :) Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Silverlight Cream for January 11, 2011 -- #1024

    - by Dave Campbell
    1,000 blogposts is quite a few, but to die-hard geeks, 1000 isn't the number... 1K is the number, and today is my 1K blogpost! I've been working up to this for at least 11 months. Way back at MIX10, I approached some vendors about an idea I had. A month ago I contacted them and others, and everyone I contacted was very generous and supportive of my idea. My idea was not to run a contest, but blog as normal, and whoever ended up on my 1K post would get some swag... and I set a cut-off at 13 posts. So... blogging normally, I had some submittals, and then ran my normal process to pick up the next posts until I hit a total of 13. To provide a distribution channel for the swag, everyone on the list, please send me your snail mail (T-shirts) and email (licenses) addresses as soon as possible.   I'd like to thank the following generous sponsors for their contributions to my fun (in alphabetic order): and Rachel Hawley for contributing 4 Silverlight control sets First Floor Software and Koen Zwikstra for contributing 13 licenses for Silverlight Spy and Sara Faatz/Jason Beres for contributing 13 licenses for Silverlight Data Visualization controls and Svetla Stoycheva for contributing T-Shirts for everyone on the post and Ina Tontcheva for contributing 13 licenses for RadControls for Silverlight + RadControls for Windows Phone and Charlene Kozlan for contributing 1 combopack standard, 2 DataGrid for Silverlight, and 2 Listbox for Silverlight Standard And now finally...in this Issue: Nigel Sampson, Jeremy Likness, Dan Wahlin, Kunal Chowdhurry, Alex Knight, Wei-Meng Lee, Michael Crump, Jesse Liberty, Peter Kuhn, Michael Washington, Tau Sick, Max Paulousky, Damian Schenkelman Above the Fold: Silverlight: "Demystifying Silverlight Dependency Properties" Dan Wahlin WP7: "Using Windows Phone Gestures as Triggers" Nigel Sampson Expression Blend: "PathListBox: making data look cool" Alex Knight From SilverlightCream.com: Using Windows Phone Gestures as Triggers Nigel Sampson blogged about WP7 Gestures, the Toolkit, and using Gestures as Triggers, and actually makes it looks simple :) Jounce Part 9: Static and Dynamic Module Management Jeremy Likness has episode 9 of his explanation of his MVVM framework, Jounce, up... and a big discussion of Modules and Module Management from a Jounce perspective. Demystifying Silverlight Dependency Properties Dan Wahlin takes a page from one of his teaching opportunities, and shares his knowledge of Dependency Properties with us... beginning with what they are, defining them in code, and demonstrating their use. Customizing Silverlight ChildWindow Style using Blend Kunal Chowdhurry has a great post up about getting your Child Windows to match the look & feel of the rest of youra app... plus a bunch of Blend goodness thrown in. PathListBox: making data look cool File this post by Alex Knight in the 'holy crap' file along with the others in this series! ... just check out that cool Ticker Style Path ListBox at the top of the blog... too cool! Web Access in Windows Phone 7 Apps Wei-Meng Lee has the 3rd part of his series on WP7 development up and in this one is discussing Web Access... I mean *discussing* it... tons of detail, code, and explanation... great post. Prevent your Silverlight XAP file from caching in your browser. Michael Crump helps relieve stress on Silverlight developers everywhere by exploring how to avoid caching of your XAP in the browser... (WPFS) MVVM Light Toolkit: Soup To Nuts Part I Jesse Liberty continues his Windows Phone from Scratch series with a new segment exploring Laurent Bugnion's MVVMLight Toolkit beginning with acquiring and installing the toolkit, then proceeds to discuss linking the View and ViewModel, the ViewModel Locator, and page navigation. Silverlight: Making a DateTimePicker Peter Kuhn attacks a problem that crops up on the forums a lot -- a DateTimePicker control for Silverlight... following the "It's so simple to build one yourself" advice, he did so, and provides the code for all of us! Windows Phone 7 Animated Button Press Michael Washington took exception to button presses that gave no visual feedback and produced a behavior that does just that. Using TweetSharp in a Windows Phone 7 app Tau Sick demonstrates using TweetSharp to put a twitter feed into a WP7 app, as he did in "Hangover Helper"... all the instructions from getting Tweeetshaprt to the code necessary. Bindable Application Bar Extensions for Windows Phone 7 Max Paulousky has a post discussing some real extensions to the ApplicationBar for WP7.. he begins with a bindable application bar by Nicolas Humann that I've missed, probably because his blog is in French... and extends it to allow using DelegateCommand. How to: Load Prism modules packaged in a separate XAP file in an OOB application Damian Schenkelman posts about Prism, AppModules in separate XAPs and running OOB... if you've tried this, you know it's a hassle.. Damian has the solution. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Silverlight Cream for February 05, 2011 -- #1041

    - by Dave Campbell
    In this Issue: Peter Kuhn, Mike Ormond(-2-, -3-), WindowsPhoneGeek, Daniel N. Egan, Phil Middlemiss(-2-), Max Paulousky, Michael Washington. Above the Fold: Silverlight: "Designing for Browser-Zoom: Part 2" Phil Middlemiss WP7: "Talking about Converters in WP7 | Coding4fun toolkit converters in depth" WindowsPhoneGeek Lightswitch: "LightSwitch: Can We Handle The Truth?" Michael Washington Shoutouts: András Velvárt has a video up of some awesome changes he has planned for SurfCube, check it out: SurfCube V2 - 3D Web Browser for Windows Phone 7, now with tabs! From SilverlightCream.com: Silverlight for keyboard junkies Peter Kuhn has a post up talking about the issues surrounding trying to use the tab key to navigate between controls... and follows it up with a behavior that resolves it. Windows Phone 7 Content On Demand Mike Ormond has a batch of WP7 Videos up... this first is "Windows Phone 7: A Different Kind of Phone" with Andrej Radinger. Windows Phone 7 Content on Demand Pt 2 Mike Ormond's 2nd WP7 video is "Understanding the Windows Phone 7 Development Tools and Getting Started" with Maarten Struys Windows Phone 7 Content on Demand Pt 3 Mike Ormond's 3rd WP7 Content on Demand is "Games Programming on Windows Phone 7 with Silverlight and XNA" with Rob Miles Talking about Converters in WP7 | Coding4fun toolkit converters in depth WindowsPhoneGeek is discussing value converters in his latest post... value converters for WP7... and the ones in the Coding4Fun toolkit to be exact... everything you wanted to know about them but didn't know to ask :) WP7 Developer Tools–Jan Update Daniel N. Egan has information up about the new WP7 Developer Tools release. Designing for Browser-Zoom: Part 1 Phil Middlemiss has both parts of a series on Browser Zoom up... this first part covers the zoom and different pieces involved. Designing for Browser-Zoom: Part 2 Phil Middlemiss's part 2 shows us some design considerations and visual states, including an attached behavior you can use in Blend to respond to the zoom event. Windows Phone Copy-Paste: How It Looks and Works Max Paulousky has the first post I've seen on WP7 Copy/Paste up... of course it's still in the emulator, but hey... that's better than nothing, right? LightSwitch: Can We Handle The Truth? Have you been playing with Lightswitch? Well... Michael Washington has, and it's got his interest up far enough that he's waving the flags trying to attract everyone else over there as well... see if you agree. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • SOA Suite 11g Database Growth Management

    - by JuergenKress
    This whitepaper “Oracle SOA Suite 11g Database Growth Management”  has been written to highlight the need to implement an appropriate strategy to manage the growth the of SOA 11g database. The advice presented should facilitate better dialog between SOA and Database administrators when planning database and host requirements Whitepaper Oracle SOA Suite 11g Database Growth Management Advisor Webcast “Oracle SOA Suite 11g Database Growth Management” April 11th 2012 Author: Michael Bousamra Contributing Authors: Deepak Arora Sai Sudarsan Pogaru SOA Partner Community For regular information on Oracle SOA Suite become a member in the SOA Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA Community Forum,SOA Specialization,purging,Michael Bousamra Contributing Authors: Deepak Arora Sai Sudarsan Pogaru,SOA Suite 11g Database Growth Management

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  • PeopleSoft at Alliance 2012 Executive Forum

    - by John Webb
    Guest Posting From Rebekah Jackson This week I jointed over 4,800 Higher Ed and Public Sector customers and partners in Nashville at our annual Alliance conference.   I got lost easily in the hallways of the sprawling Gaylord Opryland Hotel. I carried the resort map with me, and I would still stand for several minutes at a very confusing junction, studying the map and the signage on the walls. Hallways led off in many directions, some with elevators going down here and stairs going up there. When I took a wrong turn I would instantly feel stuck, lose my bearings, and occasionally even have to send out a call for help.    It strikes me that the theme for the Executive Forum this year outlines a less tangible but equally disorienting set of challenges that our higher education customer’s CIOs are facing: Making Decisions at the Intersection of Business Value, Strategic Investment, and Enterprise Technology. The forces acting upon higher education institutions today are not neat, straight-forward decision points, where one can glance to the right, glance to the left, and then quickly choose the best course of action. The operational, technological, and strategic factors that must be considered are complex, interrelated, messy…and the stakes are high. Michael Horn, co-author of “Disrupting Class: How Disruptive Innovation Will Change the Way the World Learns”, set the tone for the day. He introduced the model of disruptive innovation, which grew out of the research he and his colleagues have done on ‘Why Successful Organizations Fail’. Highly simplified, the pattern he shared is that things start out decentralized, take a leap to extreme centralization, and then experience progressive decentralization. Using computers as an example, we started with a slide rule, then developed the computer which centralized in the form of mainframes, and gradually decentralized to mini-computers, desktop computers, laptops, and now mobile devices. According to Michael, you have more computing power in your cell phone than existed on the planet 60 years ago, or was on the first rocket that went to the moon. Applying this pattern to Higher Education means the introduction of expensive and prestigious private universities, followed by the advent of state schools, then by community colleges, and now online education. Michael shared statistics that indicate 50% of students will be taking at least one on line course by 2014…and by some measures, that’s already the case today. The implication is that technology moves from being the backbone of the campus, the IT department’s domain, and pushes into the academic core of the institution. Innovative programs are underway at many schools like Bellevue and BYU Idaho, joined by startups and disruptive new players like the Khan Academy.   This presents both threat and opportunity for higher education institutions, and means that IT decisions cannot afford to be disconnected from the institution’s strategic plan. Subsequent sessions explored this theme.    Theo Bosnak, from Attain, discussed the model they use for assessing the complete picture of an institution’s financial health. Compounding the issue are the dramatic trends occurring in technology and the vendors that provide it. Ovum analyst Nicole Engelbert, shared her insights next and suggested that incremental changes are no longer an option, instead fundamental changes are affecting the landscape of enterprise technology in higher ed.    Nicole closed with her recommendation that institutions focus on the trends in higher education with an eye towards the strategic requirements and business value first. Technology then is the enabler.   The last presentation of the day was from Tom Fisher, Sr. Vice President of Cloud Services at Oracle. Tom runs the delivery arm of the Cloud Services group, and shared his thoughts candidly about his experiences with cloud deployments as well as key issues around managing costs and security in cloud deployments. Okay, we’ve covered a lot of ground at this point, from financials planning, business strategy, and cloud computing, with the possibility that half of the institutions in the US might not be around in their current form 10 years from now. Did I forget to mention that was raised in the morning session? Seems a little hard to believe, and yet Michael Horn made a compelling point. Apparently 100 years ago, 8 of the top 10 education institutions in the world were German. Today, the leading German school is ranked somewhere in the 40’s or 50’s. What will the landscape be 100 years from now? Will there be an institution from China, India, or Brazil in the top 10? As Nicole suggested, maybe US parents will be sending their children to schools overseas much sooner, faced with the ever-increasing costs of a US based education. Will corporations begin to view skill-based certification from an online provider as a viable alternative to a 4 year degree from an accredited institution, fundamentally altering the education industry as we know it?

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  • Best tutorial ever! Is there one just like it for XHTML and CSS...?

    - by Joshua C
    I have been learning Ruby on Rails using www.railstutorial.org, and I LOVE it! My only problem? Well, I can build the applications just fine, but my knowledge of designing the skin (CSS) of the application is limited. Is there a really good XHTML and CSS which is very similar to the Ruby on Rails Tutorial by Michael Hartl? If not, perhaps you can point me towards some of the best? Thanks, Joshua Collins P.S. Only if Michael would create a CSS and XHTML tutorial himself... sigh

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  • Removing Duplicate Data From SQL Query Output For Display On A Web Page [migrated]

    - by doubleJ
    I had asked a similar question on stackoverflow but didn't really get anywhere. This page shows the output that I'm currently getting from my MSSQL server. I have a table of venue information (name, address, etc...) that our events happen on. Separately, I have a table of the actual events that are scheduled (an event may happen multiple times in one day and/or over multiple days). I join those tables with this query: <?php try { $dbh = new PDO("sqlsrv:Server=localhost;Database=Sermons", "", ""); $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $sql = "SELECT TOP (100) PERCENT dbo.TblSermon.Day, dbo.TblSermon.Date, dbo.TblSermon.Time, dbo.TblSermon.Speaker, dbo.TblSermon.Series, dbo.TblSermon.Sarasota, dbo.TblSermon.NonFlc, dbo.TblJoinSermonLocation.MeetingName, dbo.TblLocation.Location, dbo.TblLocation.Pastors, dbo.TblLocation.Address, dbo.TblLocation.City, dbo.TblLocation.State, dbo.TblLocation.Zip, dbo.TblLocation.Country, dbo.TblLocation.Phone, dbo.TblLocation.Email, dbo.TblLocation.WebAddress FROM dbo.TblLocation RIGHT OUTER JOIN dbo.TblJoinSermonLocation ON dbo.TblLocation.ID = dbo.TblJoinSermonLocation.Location RIGHT OUTER JOIN dbo.TblSermon ON dbo.TblJoinSermonLocation.Sermon = dbo.TblSermon.ID WHERE (dbo.TblSermon.Date >= { fn NOW() }) ORDER BY dbo.TblSermon.Date, dbo.TblSermon.Time"; $stmt = $dbh->prepare($sql); $stmt->execute(); $stmt->setFetchMode(PDO::FETCH_ASSOC); foreach ($stmt as $row) { echo "<pre>"; print_r($row); echo "</pre>"; } unset($row); $dbh = null; } catch(PDOException $e) { echo $e->getMessage(); } ?> So, as it loops through the query results, it creates an array for each record and ends up like this: Array ( [Day] => Tuesday [Date] => 2012-10-30 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => The Ark Church [Pastors] => Alan & Joy Clayton [Address] => 450 Humble Tank Rd. [City] => Conroe [State] => TX [Zip] => 77305.0 [Phone] => (936) 756-1988 [Email] => [email protected] [WebAddress] => http://www.thearkchurch.org ) Array ( [Day] => Wednesday [Date] => 2012-10-31 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => The Ark Church [Pastors] => Alan & Joy Clayton [Address] => 450 Humble Tank Rd. [City] => Conroe [State] => TX [Zip] => 77305.0 [Phone] => (936) 756-1988 [Email] => [email protected] [WebAddress] => http://www.thearkchurch.org ) Array ( [Day] => Tuesday [Date] => 2012-11-06 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => Fellowship Of Faith Christian Center [Pastors] => Michael & Joan Kalstrup [Address] => 18999 Hwy. 59 [City] => Oakland [State] => IA [Zip] => 51560.0 [Phone] => (712) 482-3455 [Email] => [email protected] [WebAddress] => http://www.fellowshipoffaith.cc ) Array ( [Day] => Wednesday [Date] => 2012-11-14 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => Faith Family Church [Pastors] => Michael & Barbara Cameneti [Address] => 8200 Freedom Ave NW [City] => Canton [State] => OH [Zip] => 44720.0 [Phone] => (330) 492-0925 [Email] => [WebAddress] => http://www.myfaithfamily.com ) As you can see, The Ark Church and its associated contact information is duplicated, so when I work with those arrays and output them to the page, I see a bunch of duplicate content. I'd like to remove the duplicate information so that I get results similar to this: The Ark Church Alan & Joy Clayton 450 Humble Tank Rd. Conroe, TX 77305 (936) 756-1988 [email protected] http://www.thearkchurch.org Meetings: Tuesday, 2012-10-30 07:00 PM Wednesday, 2012-10-31 07:00 PM Fellowship Of Faith Christian Center Michael & Joan Kalstrup 18999 Hwy. 59 Oakland, IA 51560 (712) 482-3455 [email protected] http://www.fellowshipoffaith.cc Meetings: Tuesday, 2012-11-06 07:00 PM Faith Family Church Michael & Barbara Cameneti 8200 Freedom Ave NW Canton, OH 44720 (330) 492-0925 http://www.myfaithfamily.com Meetings: Wednesday, 2012-11-14 07:00 PM It doesn't necessarily have to end up like that (I'm not looking for code specific for these results, but a concept of how to not show the duplicated information). I'm assuming that an additional foreach or while will do it, but I haven't figured out any logic that says <?php if ($location == $previouslocation) echo ""; ?>.

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  • How can I install canon pixma ip100 driver for Ubuntu 12.04LTS 64bit?

    - by kina
    I tried installing the driver by typing the following commands in the terminal: sudo add-apt-repository ppa:michael-gruz/canon - the result was the following: You are about to add the following PPA to your system: More info: https://launchpad.net/~michael-gruz/+archive/canon Press [ENTER] to continue or ctrl-c to cancel adding it Then I typed: sudo apt-get update - the result was the following: Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /tmp/tmp.HDuHmOSJ0l --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver hkp://keyserver.ubuntu.com:80/ --recv 84E550CD36EC35430A66AC5A03396E1C3F7B4A1D gpg: requesting key 3F7B4A1D from hkp server keyserver.ubuntu.com gpg: key 3F7B4A1D: "Launchpad Misakovi" not changed gpg: Total number processed: 1 gpg: unchanged: 1 I typed the next command: sudo apt-get install cnijfilter-ip100series The return response was: Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package cnijfilter-ip100series Does anyone know the solution? Kina

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  • Office 2010 & SharePoint 2010: Platform for Innovation

    There's a great new article by Michael Desmond in Visual Studio Magazine called "Office Alignment: Why Office 2010 and SharePoint 2010 are poised to unleash a new wave of developer innovation". Read it and you'll get Michael's always engaging insight into the new products investments in this release, and you'll read about some key customers who have leveraged the platform to drive their business. I've been reading a lot about innovation, and it can be a topic that begins to elude us when we...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Strange error with VS2008 on Windows 7

    - by Christian
    We have a solution with two projects, one of them is a Silverlight 3 application which is embedded on the other ASP.NET MVC project. Just recently an error started to appear which makes the build fail. Here is the output: `------ Build started: Project: DotCoquiMap, Configuration: Debug Any CPU ------ C:\Program Files\MSBuild\Microsoft\Silverlight\v3.0\Microsoft.Ria.Client.targets : warning : Could not find necessary input file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll'. Done building project "DotCoquiMap.csproj" -- FAILED. ------ Build started: Project: DotCoquiProject, Configuration: Debug Any CPU ------ C:\Windows\Microsoft.NET\Framework\v3.5\Csc.exe /noconfig /nowarn:1701,1702 /errorreport:prompt /warn:4 /define:DEBUG;TRACE /reference:C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll /reference:..\ExternalLibraries\itextsharp.dll /reference:..\ExternalLibraries\MvcMembership.dll /reference:..\ExternalLibraries\PagedList.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Configuration.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll" /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.DataSetExtensions.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.Linq.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Drawing.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.EnterpriseServices.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Web.Abstractions.dll" /reference:............\Windows\assembly\GAC_MSIL\System.Web.DataVisualization\3.5.0.0__31bf3856ad364e35\System.Web.DataVisualization.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Web.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Web.Extensions.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Web.Mobile.dll /reference:"C:\Program Files\Microsoft ASP.NET\ASP.NET MVC 1.0\Assemblies\System.Web.Mvc.dll" /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Web.Routing.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Web.Services.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Xml.Linq.dll" /debug+ /debug:full /optimize- /out:obj\Debug\DotCoquiProject.dll /target:library Controllers\AccountController.cs Controllers\AdministrationController.cs Controllers\ApiController.cs Controllers\CampaignsCategoriesController.cs Controllers\CampaignsController.cs Controllers\CampaignsFormViewModel.cs Controllers\CampaignStatisticsController.cs Controllers\CampaignStatisticsDetailsViewModel.cs Controllers\ControllerHelpers.cs Controllers\CountriesController.cs Controllers\ErrorController.cs Controllers\HomeController.cs Controllers\MapController.cs Controllers\MediaController.cs Controllers\MediaViewModel.cs Controllers\NewsController.cs Controllers\OrganizationsController.cs Controllers\OrgCenterController.cs Controllers\UserAdministrationController.cs Default.aspx.cs Global.asax.cs Models\Campaigns.cs Models\CategoriesRuleValidation.cs Models\DotCoquiDBModel.designer.cs Models\DotCoquiRepository.cs Models\DQcodes.cs Models\FileRepository.cs Models\ISmtpClient.cs Models\JsonModels.cs Models\OrgCenter\IndexViewModel.cs Models\SmtpClientProxy.cs Models\Statistic.cs Models\User.cs Models\UserAdministration\DetailsViewModel.cs Models\UserAdministration\IndexViewModel.cs Models\UserAdministration\RoleViewModel.cs Properties\AssemblyInfo.cs error CS0006: Metadata file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll' could not be found Compile complete -- 1 errors, 0 warnings ========== Build: 0 succeeded or up-to-date, 2 failed, 0 skipped ==========` And here is the errors / warnings: Warning 2 Could not find necessary input file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll'. DotCoquiMap Error 1 Metadata file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll' could not be found DotCoquiProject The DotCoquiMap is not getting built therefore the DotCoquiProject (ASP.NET MVC) cannot find the .dll. Now here is the really odd thing, under Windows XP the very same code compiles and runs perfectly.... under windows 7 it gives us these errors. It is the very same code, we have tested it on 3 different Win7 machines to no avail. Help will be really really helpful. Thanks in advance.

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  • C++ match string in file and get line number

    - by Corey
    I have a file with the top 1000 baby names. I want to ask the user for a name...search the file...and tell the user what rank that name is for boy names and what rank for girl names. If it isn't in boy names or girl names, it tells the user it's not among the popular names for that gender. The file is laid out like this: Rank Boy-Names Girl-Names 1 Jacob Emily 2 Michael Emma . . . Desired output for input Michael would be: Michael is 2nd most popular among boy names. If Michael is not in girl names it should say: Michael is not among the most popular girl names Though if it was, it would say: Micheal is (rank) among girl names The code I have so far is below.. I can't seem to figure it out. Thanks for any help. #include <iostream> #include <fstream> #include <string> #include <cctype> using namespace std; void find_name(string name); int main(int argc, char **argv) { string name; cout << "Please enter a baby name to search for:\n"; cin >> name; /*while(!(cin>>name)) { cout << "Please enter a baby name to search for:\n"; cin >> name; }*/ find_name(name); cin.get(); cin.get(); return 0; } void find_name(string name) { ifstream input; int line = 0; string line1 = " "; int rank; string boy_name = ""; string girl_name = ""; input.open("/<path>/babynames2004.rtf"); if (!input) { cout << "Unable to open file\n"; exit(1); } while(input.good()) { while(getline(input,line1)) { input >> rank >> boy_name >> girl_name; if (boy_name == name) { cout << name << " is ranked " << rank << " among boy names\n"; } else { cout << name << " is not among the popular boy names\n"; } if (girl_name == name) { cout << name << " is ranked " << rank << " among girl names\n"; } else { cout << name << " is not among the popular girl names\n"; } } } input.close(); }

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  • C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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  • C#/.NET Little Wonders: The ConcurrentDictionary

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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  • no mails routed to/from new Exchange 2010

    - by Michael
    I have an Exchange Server 2003 up and running for years. Now I am in the mid of transition to Exchange Server 2010, I already installed it, put the latest Servicepack on it and everything seems fine, BUT: Mails do not get delivered to MailBoxes on the new Exchange 2010. e.g. when I create a new mailbox on the old server, Emails in and out to/from it work like a charm. But as soon as I move it to the new server, emails get stuck. Noe delivered from outside or old mailboxes, not send out from the new server to enywhere. Sending between Mailboxes on the new Server of course is working. I can see the connectors between old and new Server in the Exchange 2003 Admin Tool, but I cannot find these nowhere on the new server. I have also setup sending connectors at the new server to send out mails directly, but that does not work. In all other areas, the servers are perfectly working together - moving mailboxes between, seeing each other etc. "just" they dont exchange (!) any emails - Any ideas what I missed? I also followed the hints from: Upgrading from Exchange 2003 to Exchange 2010, routing works in one direction only There Emails were transported at least in one direction, in my case they are not transported at all. Both my connectors are up and valid abd have the correct source/target shown on Get-RoutingGroupConnector | FL Kind regards Michael

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  • DNS issue for internal website routing internet connection from remote location

    - by Michael Paul
    I have an issue that I could use some help with. Our company has a main location and a remote location. Previously, the remote location was connected to the main location through an internet connection VPN tunnel. The connection was pitifully slow at 1.5Mbps, so we upgraded it with a 75Mbps direct link. That meant the remote location lost it's internet access, so we routed their access through the main office internet connection. Everything works perfect except for one thing. The website we host is not accessible from the remote location unless the IP address is used. If I do NSLOOKUP on our website address from a machine connected to the main location network, it resolves correctly to the inside IP address. However, if I do the same from a remote location machine, it resolves to the website's outside IP address. Our internal DNS server(s) have a pointer and CNAME records set up, and everything was working perfectly before the connection was upgraded. In addition, the remote location has a domain controller, DNS server and DHCP server to service these requests at the remote location and prevent these requests from getting routed back and forth over the link. So I think was it happening is that for some reason the DNS server at the remote location is not resolving our website name correctly and passing the requests on to the routers, which then push the request out to the internet DNS system. That resolves the name to our external IP. This is purely a DNS issue, everything else works just fine. I am just stumped on this one. Any ideas on how to fix this? Edit: I forgot to mention that at the remote side of the link is a Cisco ASA-5505 and at the main office there is a Cisco ASA-5510. The link is connected between these 2 devices and the routing is handled in the 5510. Thanks, Michael

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  • STOP 0x7b booting from iSCSI

    - by Michael
    Hi, I've a Windows 2008 SBS running. It boots of iSCSI. That setup worked for months until yesterday. I intended to reboot and gained a: STOP 0x0000007b INACCESSIBLE_BOOT_DEVICE and no idea why. My setup hasn't changed. No new controller, no new or changed iSCSI targets, no new Network Card or IP address changes. I had all Windows Updates on it. Last known good: same STOP. Allow unsigned drivers: same STOP. Safe mode (all variants): same STOP. Mount target from a client: works. Filesystem check fine. I booted of the SBS DVD but in computer repair options my target doesn't appear. When i choose setup the target appears. So, how can i diagnose what's going wrong? Any helpful tools? Any hints? Thanks in advance Michael

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  • LINQ to Entities for subtracting 2 dates

    - by Michael I
    I am trying to determine the number of days between 2 dates using LINQ with Entity Framework. It is telling me that it does not recognize Subtract on the System.TimeSpan class Here is my where portion of the LINQ query. where ((DateTime.Now.Subtract(vid.CreatedDate).TotalDays < maxAgeInDays)) Here is the error I receive in the VS.NET debugger {"LINQ to Entities does not recognize the method 'System.TimeSpan Subtract(System.DateTime)' method, and this method cannot be translated into a store expression."} Am I doing something wrong or is there a better way to get the number of days between 2 DateTimes in the entity framework? thanks Michael

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  • "Gtk-WARNING **: cannot open display: " when using execve to launch a Gtk program on ubuntu

    - by michael
    Hi, I have the following c program which launches a Gtk Program on ubuntu: #include <unistd.h> int main( int argc, const char* argv[] ) { char *args[2] = { "testarg", 0 }; char *envp[1] = { 0 }; execve("/home/michael/MyGtkApp",args,envp); } I get "Gtk-WARNING **: cannot open display: " and my program is not launched. I have tried setting char *envp[1] = {"DISPLAY:0.0"}; and execute 'xhost +' , I dont' see the 'cannot open display' warning, but my program is still not launched. Does anyone know how to fix my problem? Thank you.

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  • Read half precision float (float16 IEEE 754r) binary data in matlab

    - by Michael
    you have been a great help last time, i hope you can give me some advise this time, too. I read a binary file into matlab with bit16 (format = bitn) and i get a string of ones and zeros. bin = '1 00011 1111111111' (16 bits: 1. sign, 2-6. exponent, 7-16. mantissa) According to ftp://www.fox-toolkit.org/pub/fasthalffloatconversion.pdf it can be 'converted' like out = (-1)^bin(1) * 2^(bin(2:6)-15) * 1.bin(7:16) [are exponent and mantissa still binary?] Can someone help me out and tell me how to deal with the 'eeeee' and '1.mmmmmmmmmm' as mentioned in the pdf, please. Thanks a lot! Michael

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  • Problem with Richfaces running with NGinx proxy

    - by Michael
    Hi, I got a problem with my Richfaces application. I am using it with JSF and GlassFish v.2 on my localhost and combination od dataTable and dataScroller works fine. While moving the app to the VPS running Tomcat but proxied by Nginx server, everything crashes. Exactly the scroller is working, but the dataTable view is not refreshed! I looked at responses with Firebug and figured out, that even on VPS the response contains 2nd page of the dataTable, but it is not shown on the screen. I tried everything - changing page attribute of dataScroller (it was taken from session bean, I changed that to request bean). I also removed page attribute from dataScroller - did not help either. Finally I added my table to reRender attribute of dataScroller - still whichever page I choose I am seeing only the first one. Does anyone even heard about such problem? I am going crazy with this. Best regards, Michael

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  • Attached Property Changed Event?

    - by Michael Menne
    Hello, ist there a way to get a change notification if an attached property changed? A simple example is a Canvas with a Rectangle in it. The position of the Rectange is set by using the DepenendyProperties Canvas.Top and Canvas.Left. I'm using an Adorner to move the Rectangle around by changing the Canvas.Top and Canvas.Left. <Canvas Width="500" Height="500" > <Rectangle Width="40" Height="40" Canvas.Left="10" Canvas.Top="20" /> </Canvas> The next step is to create an Arrow between two Rectangles. In order to keep track of the moving Rectangles the Arrow must get a change notification whenever the position of a Rectanglechanges. This would be easy if I could just get a changed notification when the Attached Property Canvas.Topchanges. Thanks for any help, Michael

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  • python: subclass a metaclass

    - by Michael Konietzny
    Hello, for putting methods of various classes into a global registry I'm using a decorator with a metaclass. The decorator tags, the metaclass puts the function in the registry: class ExposedMethod (object): def __init__(self, decoratedFunction): self._decoratedFunction = decoratedFunction def __call__(__self,*__args,**__kw): return __self._decoratedFunction(*__args,**__kw) class ExposedMethodDecoratorMetaclass(type): def __new__(mcs, name, bases, dct): for obj_name, obj in dct.iteritems(): if isinstance(obj, ExposedMethod): WorkerFunctionRegistry.addWorkerToWorkerFunction(obj_name, name) return type.__new__(mcs, name, bases, dct) class MyClass (object): __metaclass__ = DiscoveryExposedMethodDecoratorMetaclass @ExposeDiscoveryMethod def myCoolExposedMethod (self): pass I've now came to the point where two function registries are needed. The first thought was to subclass the metaclass and put the other registry in. For that the new method has simply to be rewritten. Since rewriting means redundant code this is not what I really want. So, it would be nice if anyone could name a way how to put an attribute inside of the metaclass which is able to be read when new is executed. With that the right registry could be put in without having to rewrite new. Thanks and Greetings, Michael

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  • Conditional Validation with Paperclip difficult

    - by Michael Schmitz
    Hi, I have an "item", which goes through a multi-page creation process. Images are uploaded at step five, and I keep track of the steps by using the attribute "complete". When validating whether an image is attached with paperclip, I get problems using the code below: validates_attachment_presence :pic1, :if => Proc.new { |u| u.complete == "step5"} It seems that I can't access the "complete" attribute, as the active-record object seems to be the paperclip image. Is there a way for me to check at which point in the process I am and validate conditionally? Thanks, Michael

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